1965 Vintage Andersen Window sash balances

A handy person from Lewiston, New York 14092 says:
June 13, 2017
I am looking to replace the sash balancers on this Andersen window. It is all wooden construction with a measurement of 23-3/4" x 40-1/4" for the thermo-pane glass. The existing balancer is marked dd12 33 27 on the corner. The balancer dimensions are 6-5/16"x2-13/16"x3/4". I have more photographs if needed but his web-page wouldn't allow their inclusion. These balance units have galvanized steel shims installed along side them too. Seems a bit strange!

Thank you,
User submitted image of their window hardware.
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Tom from SWISCO responded:
June 16, 2017
Thank you for your post. Please take a look at our 24-1231 Andersen sash balance as a match to what you have.
Andersen Sash Balance, 1226, 1227, 1231
Andersen Sash Balance, 1226, 1227, 1231
24-1231
$54.20
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